
<!DOCTYPE HTML>
<html lang="" >
    <head>
        <meta charset="UTF-8">
        <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
        <title>4.4. reaction · MobX 中文文档</title>
        <meta http-equiv="X-UA-Compatible" content="IE=edge" />
        <meta name="description" content="">
        <meta name="generator" content="GitBook 3.2.2">
        
        
        
    
    <link rel="stylesheet" href="../gitbook/style.css">

    
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-anchors/plugin.css">
                
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-highlight/website.css">
                
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-search/search.css">
                
            
                
                <link rel="stylesheet" href="../gitbook/gitbook-plugin-fontsettings/website.css">
                
            
        

    

    
        
    
        
    
        
    
        
    
        
    
        
    

        
    
    
    
    <meta name="HandheldFriendly" content="true"/>
    <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
    <meta name="apple-mobile-web-app-capable" content="yes">
    <meta name="apple-mobile-web-app-status-bar-style" content="black">
    <link rel="apple-touch-icon-precomposed" sizes="152x152" href="../gitbook/images/apple-touch-icon-precomposed-152.png">
    <link rel="shortcut icon" href="../gitbook/images/favicon.ico" type="image/x-icon">

    
    <link rel="next" href="observer-component.html" />
    
    
    <link rel="prev" href="when.html" />
    

    <style>
    @media only screen and (max-width: 640px) {
        .book-header .hidden-mobile {
            display: none;
        }
    }
    </style>
    <script>
        window["gitbook-plugin-github-buttons"] = {"buttons":[{"user":"SangKa","repo":"MobX-Docs-CN","type":"star","size":"small","count":true},{"user":"SangKa","repo":"MobX-Docs-CN","type":"fork","size":"small","count":true}]};
    </script>

    </head>
    <body>
        
<div class="book">
    <div class="book-summary">
        
            
<div id="book-search-input" role="search">
    <input type="text" placeholder="Type to search" />
</div>

            
                <nav role="navigation">
                


<ul class="summary">
    
    

    

    
        
        
    
        <li class="chapter " data-level="1.1" data-path="../">
            
                <a href="../">
            
                    
                    1. MobX 介绍
            
                </a>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.1.1" data-path="../intro/overview.html">
            
                <a href="../intro/overview.html">
            
                    
                    1.1. MobX 要点
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.1.2" data-path="../intro/concepts.html">
            
                <a href="../intro/concepts.html">
            
                    
                    1.2. 概念与原则
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.2" data-path="api.html">
            
                <a href="api.html">
            
                    
                    2. API概览
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3" >
            
                <span>
            
                    
                    3. observable 相关
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.3.1" data-path="observable.html">
            
                <a href="observable.html">
            
                    
                    3.1. observable
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.2" data-path="observable-decorator.html">
            
                <a href="observable-decorator.html">
            
                    
                    3.2. @observable
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.3" data-path="object.html">
            
                <a href="object.html">
            
                    
                    3.3. objects
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.4" data-path="array.html">
            
                <a href="array.html">
            
                    
                    3.4. arrays
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.5" data-path="map.html">
            
                <a href="map.html">
            
                    
                    3.5. maps
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.6" data-path="boxed.html">
            
                <a href="boxed.html">
            
                    
                    3.6. boxed values
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.3.7" data-path="modifiers.html">
            
                <a href="modifiers.html">
            
                    
                    3.7 decorators
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.4" >
            
                <span>
            
                    
                    4. 对 observables 作出响应
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.4.1" data-path="computed-decorator.html">
            
                <a href="computed-decorator.html">
            
                    
                    4.1. (@)computed
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.2" data-path="autorun.html">
            
                <a href="autorun.html">
            
                    
                    4.2. autorun
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.3" data-path="when.html">
            
                <a href="when.html">
            
                    
                    4.3. when
            
                </a>
            

            
        </li>
    
        <li class="chapter active" data-level="1.4.4" data-path="reaction.html">
            
                <a href="reaction.html">
            
                    
                    4.4. reaction
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.5" data-path="observer-component.html">
            
                <a href="observer-component.html">
            
                    
                    4.5. (@)observer
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.4.6" data-path="../best/react.html">
            
                <a href="../best/react.html">
            
                    
                    4.6. 理解 MobX 对何作出响应
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.5" >
            
                <span>
            
                    
                    5. 改变 observables
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.5.1" data-path="action.html">
            
                <a href="action.html">
            
                    
                    5.1. action
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.2" data-path="../best/actions.html">
            
                <a href="../best/actions.html">
            
                    
                    5.2. async actions & flows
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.5.3" data-path="object-api.html">
            
                <a href="object-api.html">
            
                    
                    5.3. Object api
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.6" >
            
                <span>
            
                    
                    6. 工具函数
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.6.1" data-path="tojson.html">
            
                <a href="tojson.html">
            
                    
                    6.1. toJS
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.2" data-path="extend-observable.html">
            
                <a href="extend-observable.html">
            
                    
                    6.2. extendObservable
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.3" data-path="extending.html">
            
                <a href="extending.html">
            
                    
                    6.3. createAtom
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.4" data-path="observe.html">
            
                <a href="observe.html">
            
                    
                    6.4. intercept & observe
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.5" >
            
                <a target="_blank" href="https://github.com/mobxjs/mobx-utils#frompromise">
            
                    
                    6.5. mobxUtils.fromPromise
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.6" >
            
                <a target="_blank" href="https://github.com/mobxjs/mobx-utils#fromresource">
            
                    
                    6.6. mobxUtils.fromResource
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.7" >
            
                <a target="_blank" href="https://github.com/mobxjs/mobx-utils#tostream">
            
                    
                    6.7. mobxUtils.toStream
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.8" >
            
                <a target="_blank" href="https://github.com/mobxjs/mobx-utils#fromstream">
            
                    
                    6.8. mobxUtils.fromStream
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.9" >
            
                <a target="_blank" href="https://github.com/mobxjs/mobx-utils#now">
            
                    
                    6.9. mobxUtils.now
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.10" data-path="create-transformer.html">
            
                <a href="create-transformer.html">
            
                    
                    6.10. mobxUtils.createTransformer
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.11" data-path="expr.html">
            
                <a href="expr.html">
            
                    
                    6.11. mobxUtils.expr
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.6.12" data-path="api.html">
            
                <a href="api.html">
            
                    
                    6.12. complete api overview
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.7" >
            
                <a target="_blank" href="https://github.com/mobxjs/awesome-mobx#examples">
            
                    
                    7. 博客、 视频及相关项目
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8" >
            
                <span>
            
                    
                    8. 贴士与技巧
            
                </span>
            

            
            <ul class="articles">
                
    
        <li class="chapter " data-level="1.8.1" data-path="../faq/faq.html">
            
                <a href="../faq/faq.html">
            
                    
                    8.1. 常见问题解答
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.2" data-path="../best/pitfalls.html">
            
                <a href="../best/pitfalls.html">
            
                    
                    8.2. 常见陷阱与最佳实践
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.3" data-path="../best/decorators.html">
            
                <a href="../best/decorators.html">
            
                    
                    8.3. 如何(不)使用装饰器
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.4" data-path="../best/trace.html">
            
                <a href="../best/trace.html">
            
                    
                    8.4. 使用 trace 进行调试
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.5" data-path="../best/store.html">
            
                <a href="../best/store.html">
            
                    
                    8.5. 定义数据存储
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.6" data-path="../best/react-performance.html">
            
                <a href="../best/react-performance.html">
            
                    
                    8.6. 优化 React 组件
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.7" data-path="../best/devtools.html">
            
                <a href="../best/devtools.html">
            
                    
                    8.7. 开发工具
            
                </a>
            

            
        </li>
    
        <li class="chapter " data-level="1.8.8" data-path="spy.html">
            
                <a href="spy.html">
            
                    
                    8.8. spy
            
                </a>
            

            
        </li>
    

            </ul>
            
        </li>
    
        <li class="chapter " data-level="1.9" data-path="../donating.html">
            
                <a href="../donating.html">
            
                    
                    9. 捐赠
            
                </a>
            

            
        </li>
    

    

    <li class="divider"></li>

    <li>
        <a href="https://www.gitbook.com" target="blank" class="gitbook-link">
            Published with GitBook
        </a>
    </li>
</ul>


                </nav>
            
        
    </div>

    <div class="book-body">
        
            <div class="body-inner">
                
                    

<div class="book-header" role="navigation">
    

    <!-- Title -->
    <h1>
        <i class="fa fa-circle-o-notch fa-spin"></i>
        <a href=".." >4.4. reaction</a>
    </h1>
</div>




                    <div class="page-wrapper" tabindex="-1" role="main">
                        <div class="page-inner">
                            
<div id="book-search-results">
    <div class="search-noresults">
    
                                <section class="normal markdown-section">
                                
                                <h1 id="reaction"><a name="reaction" class="plugin-anchor" href="#reaction"><i class="fa fa-link" aria-hidden="true"></i></a>Reaction</h1>
<p>&#x7528;&#x6CD5;: <code>reaction(() =&gt; data, (data, reaction) =&gt; { sideEffect }, options?)</code>&#x3002;</p>
<p><code>autorun</code> &#x7684;&#x53D8;&#x79CD;&#xFF0C;&#x5BF9;&#x4E8E;&#x5982;&#x4F55;&#x8FFD;&#x8E2A; observable &#x8D4B;&#x4E88;&#x4E86;&#x66F4;&#x7EC6;&#x7C92;&#x5EA6;&#x7684;&#x63A7;&#x5236;&#x3002;
&#x5B83;&#x63A5;&#x6536;&#x4E24;&#x4E2A;&#x51FD;&#x6570;&#x53C2;&#x6570;&#xFF0C;&#x7B2C;&#x4E00;&#x4E2A;(<em>&#x6570;&#x636E;</em> &#x51FD;&#x6570;)&#x662F;&#x7528;&#x6765;&#x8FFD;&#x8E2A;&#x5E76;&#x8FD4;&#x56DE;&#x6570;&#x636E;&#x4F5C;&#x4E3A;&#x7B2C;&#x4E8C;&#x4E2A;&#x51FD;&#x6570;(<em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;)&#x7684;&#x8F93;&#x5165;&#x3002;
&#x4E0D;&#x540C;&#x4E8E; <code>autorun</code> &#x7684;&#x662F;&#x5F53;&#x521B;&#x5EFA;&#x65F6;<em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;&#x4E0D;&#x4F1A;&#x76F4;&#x63A5;&#x8FD0;&#x884C;&#xFF0C;&#x53EA;&#x6709;&#x5728;&#x6570;&#x636E;&#x8868;&#x8FBE;&#x5F0F;&#x9996;&#x6B21;&#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x65B0;&#x503C;&#x540E;&#x624D;&#x4F1A;&#x8FD0;&#x884C;&#x3002;
&#x5728;&#x6267;&#x884C; <em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;&#x65F6;&#x8BBF;&#x95EE;&#x7684;&#x4EFB;&#x4F55; observable &#x90FD;&#x4E0D;&#x4F1A;&#x88AB;&#x8FFD;&#x8E2A;&#x3002;</p>
<p><code>reaction</code> &#x8FD4;&#x56DE;&#x4E00;&#x4E2A;&#x6E05;&#x7406;&#x51FD;&#x6570;&#x3002;</p>
<p>&#x4F20;&#x5165; <code>reaction</code> &#x7684;&#x7B2C;&#x4E8C;&#x4E2A;&#x51FD;&#x6570;(&#x526F;&#x4F5C;&#x7528;&#x51FD;&#x6570;)&#x5F53;&#x8C03;&#x7528;&#x65F6;&#x4F1A;&#x63A5;&#x6536;&#x4E24;&#x4E2A;&#x53C2;&#x6570;&#x3002;
&#x7B2C;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#x662F;&#x7531; <em>data</em> &#x51FD;&#x6570;&#x8FD4;&#x56DE;&#x7684;&#x503C;&#x3002;
&#x7B2C;&#x4E8C;&#x4E2A;&#x53C2;&#x6570;&#x662F;&#x5F53;&#x524D;&#x7684; reaction&#xFF0C;&#x53EF;&#x4EE5;&#x7528;&#x6765;&#x5728;&#x6267;&#x884C;&#x671F;&#x95F4;&#x6E05;&#x7406; <code>reaction</code> </p>
<p>&#x503C;&#x5F97;&#x6CE8;&#x610F;&#x7684;&#x662F; <em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;<strong>&#x4EC5;</strong>&#x5BF9;&#x6570;&#x636E;&#x51FD;&#x6570;&#x4E2D;<strong>&#x8BBF;&#x95EE;</strong>&#x7684;&#x6570;&#x636E;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;&#xFF0C;&#x8FD9;&#x53EF;&#x80FD;&#x4F1A;&#x6BD4;&#x5B9E;&#x9645;&#x5728;&#x6548;&#x679C;&#x51FD;&#x6570;&#x4F7F;&#x7528;&#x7684;&#x6570;&#x636E;&#x8981;&#x5C11;&#x3002;
&#x6B64;&#x5916;&#xFF0C;<em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;&#x53EA;&#x4F1A;&#x5728;&#x8868;&#x8FBE;&#x5F0F;&#x8FD4;&#x56DE;&#x7684;&#x6570;&#x636E;&#x53D1;&#x751F;&#x66F4;&#x6539;&#x65F6;&#x89E6;&#x53D1;&#x3002;
&#x6362;&#x53E5;&#x8BDD;&#x8BF4;: <code>reaction</code>&#x9700;&#x8981;&#x4F60;&#x751F;&#x4EA7; <em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;&#x4E2D;&#x6240;&#x9700;&#x8981;&#x7684;&#x4E1C;&#x897F;&#x3002;</p>
<h2 id="&#x9009;&#x9879;"><a name="&#x9009;&#x9879;" class="plugin-anchor" href="#&#x9009;&#x9879;"><i class="fa fa-link" aria-hidden="true"></i></a>&#x9009;&#x9879;</h2>
<p>Reaction &#x63A5;&#x6536;&#x7B2C;&#x4E09;&#x4E2A;&#x53C2;&#x6570;&#xFF0C;&#x5B83;&#x662F;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#x5BF9;&#x8C61;&#xFF0C;&#x6709;&#x5982;&#x4E0B;&#x53EF;&#x9009;&#x7684;&#x53C2;&#x6570;:</p>
<ul>
<li><code>fireImmediately</code>: &#x5E03;&#x5C14;&#x503C;&#xFF0C;&#x7528;&#x6765;&#x6807;&#x8BC6;&#x6548;&#x679C;&#x51FD;&#x6570;&#x662F;&#x5426;&#x5728;&#x6570;&#x636E;&#x51FD;&#x6570;&#x7B2C;&#x4E00;&#x6B21;&#x8FD0;&#x884C;&#x540E;&#x7ACB;&#x5373;&#x89E6;&#x53D1;&#x3002;&#x9ED8;&#x8BA4;&#x503C;&#x662F; <code>false</code> &#x3002;</li>
<li><code>delay</code>: &#x53EF;&#x7528;&#x4E8E;&#x5BF9;&#x6548;&#x679C;&#x51FD;&#x6570;&#x8FDB;&#x884C;&#x53BB;&#x6296;&#x52A8;&#x7684;&#x6570;&#x5B57;(&#x4EE5;&#x6BEB;&#x79D2;&#x4E3A;&#x5355;&#x4F4D;)&#x3002;&#x5982;&#x679C;&#x662F; 0(&#x9ED8;&#x8BA4;&#x503C;) &#x7684;&#x8BDD;&#xFF0C;&#x90A3;&#x4E48;&#x4E0D;&#x4F1A;&#x8FDB;&#x884C;&#x53BB;&#x6296;&#x3002;</li>
<li><code>equals</code>: &#x9ED8;&#x8BA4;&#x503C;&#x662F; <code>comparer.default</code> &#x3002;&#x5982;&#x679C;&#x6307;&#x5B9A;&#x7684;&#x8BDD;&#xFF0C;&#x8FD9;&#x4E2A;&#x6BD4;&#x8F83;&#x5668;&#x51FD;&#x6570;&#x88AB;&#x7528;&#x6765;&#x6BD4;&#x8F83;&#x7531; <em>&#x6570;&#x636E;</em> &#x51FD;&#x6570;&#x4EA7;&#x751F;&#x7684;&#x524D;&#x4E00;&#x4E2A;&#x503C;&#x548C;&#x540E;&#x4E00;&#x4E2A;&#x503C;&#x3002;&#x53EA;&#x6709;&#x6BD4;&#x8F83;&#x5668;&#x51FD;&#x6570;&#x8FD4;&#x56DE; false <em>&#x6548;&#x679C;</em> &#x51FD;&#x6570;&#x624D;&#x4F1A;&#x88AB;&#x8C03;&#x7528;&#x3002;&#x6B64;&#x9009;&#x9879;&#x5982;&#x679C;&#x6307;&#x5B9A;&#x7684;&#x8BDD;&#xFF0C;&#x4F1A;&#x8986;&#x76D6; <code>compareStructural</code> &#x9009;&#x9879;&#x3002;</li>
<li><code>name</code>: &#x5B57;&#x7B26;&#x4E32;&#xFF0C;&#x7528;&#x4E8E;&#x5728;&#x4F8B;&#x5982;&#x50CF; <a href="spy.html"><code>spy</code></a> &#x8FD9;&#x6837;&#x4E8B;&#x4EF6;&#x4E2D;&#x7528;&#x4F5C;&#x6B64; reaction &#x7684;&#x540D;&#x79F0;&#x3002;</li>
<li><code>onError</code>: &#x7528;&#x6765;&#x5904;&#x7406; reaction &#x7684;&#x9519;&#x8BEF;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x4F20;&#x64AD;&#x5B83;&#x4EEC;&#x3002;</li>
<li><code>scheduler</code>: &#x8BBE;&#x7F6E;&#x81EA;&#x5B9A;&#x4E49;&#x8C03;&#x5EA6;&#x5668;&#x4EE5;&#x51B3;&#x5B9A;&#x5982;&#x4F55;&#x8C03;&#x5EA6; autorun &#x51FD;&#x6570;&#x7684;&#x91CD;&#x65B0;&#x8FD0;&#x884C;</li>
</ul>
<h2 id="&#x793A;&#x4F8B;"><a name="&#x793A;&#x4F8B;" class="plugin-anchor" href="#&#x793A;&#x4F8B;"><i class="fa fa-link" aria-hidden="true"></i></a>&#x793A;&#x4F8B;</h2>
<p>&#x5728;&#x4E0B;&#x9762;&#x7684;&#x793A;&#x4F8B;&#x4E2D;&#xFF0C;<code>reaction1</code>&#x3001;<code>reaction2</code> &#x548C; <code>autorun1</code> &#x90FD;&#x4F1A;&#x5BF9; <code>todos</code> &#x6570;&#x7EC4;&#x4E2D;&#x7684; todo &#x7684;&#x6DFB;&#x52A0;&#x3001;&#x5220;&#x9664;&#x6216;&#x66FF;&#x6362;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;&#x3002;
&#x4F46;&#x53EA;&#x6709; <code>reaction2</code> &#x548C; <code>autorun</code> &#x4F1A;&#x5BF9;&#x67D0;&#x4E2A; todo &#x7684; <code>title</code> &#x53D8;&#x5316;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;&#xFF0C;&#x56E0;&#x4E3A;&#x5728; <code>reaction2</code> &#x7684;&#x6570;&#x636E;&#x8868;&#x8FBE;&#x5F0F;&#x4E2D;&#x4F7F;&#x7528;&#x4E86; <code>title</code>&#xFF0C;&#x800C; <code>reaction1</code> &#x7684;&#x6570;&#x636E;&#x8868;&#x8FBE;&#x5F0F;&#x6CA1;&#x6709;&#x4F7F;&#x7528;&#x3002;
<code>autorun</code> &#x8FFD;&#x8E2A;&#x5B8C;&#x6574;&#x7684;&#x526F;&#x4F5C;&#x7528;&#xFF0C;&#x56E0;&#x6B64;&#x5B83;&#x5C06;&#x59CB;&#x7EC8;&#x6B63;&#x786E;&#x89E6;&#x53D1;&#xFF0C;&#x4F46;&#x4E5F;&#x66F4;&#x5BB9;&#x6613;&#x610F;&#x5916;&#x5730;&#x8BBF;&#x95EE;&#x76F8;&#x5173;&#x6570;&#x636E;&#x3002;
&#x8FD8;&#x53EF;&#x53C2;&#x89C1; <a href="../best/react">MobX &#x4F1A;&#x5BF9;&#x4EC0;&#x4E48;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;?</a>.</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> todos = observable([
    {
        title: <span class="hljs-string">&quot;Make coffee&quot;</span>,
        done: <span class="hljs-literal">true</span>,
    },
    {
        title: <span class="hljs-string">&quot;Find biscuit&quot;</span>,
        done: <span class="hljs-literal">false</span>
    }
]);

<span class="hljs-comment">// reaction &#x7684;&#x9519;&#x8BEF;&#x7528;&#x6CD5;: &#x5BF9; length &#x7684;&#x53D8;&#x5316;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;, &#x800C;&#x4E0D;&#x662F; title &#x7684;&#x53D8;&#x5316;!</span>
<span class="hljs-keyword">const</span> reaction1 = reaction(
    () =&gt; todos.length,
    length =&gt; <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&quot;reaction 1:&quot;</span>, todos.map(todo =&gt; todo.title).join(<span class="hljs-string">&quot;, &quot;</span>))
);

<span class="hljs-comment">// reaction &#x7684;&#x6B63;&#x786E;&#x7528;&#x6CD5;: &#x5BF9; length &#x548C; title &#x7684;&#x53D8;&#x5316;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;</span>
<span class="hljs-keyword">const</span> reaction2 = reaction(
    () =&gt; todos.map(todo =&gt; todo.title),
    titles =&gt; <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&quot;reaction 2:&quot;</span>, titles.join(<span class="hljs-string">&quot;, &quot;</span>))
);

<span class="hljs-comment">// autorun &#x5BF9;&#x5B83;&#x51FD;&#x6570;&#x4E2D;&#x4F7F;&#x7528;&#x7684;&#x4EFB;&#x4F55;&#x4E1C;&#x897F;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;</span>
<span class="hljs-keyword">const</span> autorun1 = autorun(
    () =&gt; <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&quot;autorun 1:&quot;</span>, todos.map(todo =&gt; todo.title).join(<span class="hljs-string">&quot;, &quot;</span>))
);

todos.push({ title: <span class="hljs-string">&quot;explain reactions&quot;</span>, done: <span class="hljs-literal">false</span> });
<span class="hljs-comment">// &#x8F93;&#x51FA;:</span>
<span class="hljs-comment">// reaction 1: Make coffee, find biscuit, explain reactions</span>
<span class="hljs-comment">// reaction 2: Make coffee, find biscuit, explain reactions</span>
<span class="hljs-comment">// autorun 1: Make coffee, find biscuit, explain reactions</span>

todos[<span class="hljs-number">0</span>].title = <span class="hljs-string">&quot;Make tea&quot;</span>
<span class="hljs-comment">// &#x8F93;&#x51FA;:</span>
<span class="hljs-comment">// reaction 2: Make tea, find biscuit, explain reactions</span>
<span class="hljs-comment">// autorun 1: Make tea, find biscuit, explain reactions</span>
</code></pre>
<p>&#x5728;&#x4E0B;&#x9762;&#x7684;&#x793A;&#x4F8B;&#x4E2D;&#xFF0C;<code>reaction3</code> &#x4F1A;&#x5BF9; <code>counter</code> &#x4E2D;&#x7684; count &#x4F5C;&#x51FA;&#x53CD;&#x5E94;&#x3002;
&#x5F53;&#x8C03;&#x7528; <code>reaction</code> &#x65F6;&#xFF0C;&#x7B2C;&#x4E8C;&#x4E2A;&#x53C2;&#x6570;&#x4F1A;&#x4F5C;&#x4E3A;&#x6E05;&#x7406;&#x51FD;&#x6570;&#x4F7F;&#x7528;&#x3002;
&#x4E0B;&#x9762;&#x7684;&#x793A;&#x4F8B;&#x5C55;&#x793A;&#x4E86; <code>reaction</code> &#x53EA;&#x4F1A;&#x8C03;&#x7528;&#x4E00;&#x6B21;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> counter = observable({ count: <span class="hljs-number">0</span> });

<span class="hljs-comment">// &#x53EA;&#x8C03;&#x7528;&#x4E00;&#x6B21;&#x5E76;&#x6E05;&#x7406;&#x6389; reaction : &#x5BF9; observable &#x503C;&#x4F5C;&#x51FA;&#x53CD;&#x5E94;&#x3002;</span>
<span class="hljs-keyword">const</span> reaction3 = reaction(
    () =&gt; counter.count,
    (count, reaction) =&gt; {
        <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&quot;reaction 3: invoked. counter.count = &quot;</span> + count);
        reaction.dispose();
    }
);

counter.count = <span class="hljs-number">1</span>;
<span class="hljs-comment">// &#x8F93;&#x51FA;:</span>
<span class="hljs-comment">// reaction 3: invoked. counter.count = 1</span>

counter.count = <span class="hljs-number">2</span>;
<span class="hljs-comment">// &#x8F93;&#x51FA;:</span>
<span class="hljs-comment">// (There are no logging, because of reaction disposed. But, counter continue reaction)</span>

<span class="hljs-built_in">console</span>.log(counter.count);
<span class="hljs-comment">// &#x8F93;&#x51FA;:</span>
<span class="hljs-comment">// 2</span>
</code></pre>
<p>&#x7C97;&#x7565;&#x5730;&#x8BB2;&#xFF0C;reaction &#x662F; <code>computed(expression).observe(action(sideEffect))</code> &#x6216; <code>autorun(() =&gt; action(sideEffect)(expression))</code> &#x7684;&#x8BED;&#x6CD5;&#x7CD6;&#x3002;</p>

                                
                                </section>
                            
    </div>
    <div class="search-results">
        <div class="has-results">
            
            <h1 class="search-results-title"><span class='search-results-count'></span> results matching "<span class='search-query'></span>"</h1>
            <ul class="search-results-list"></ul>
            
        </div>
        <div class="no-results">
            
            <h1 class="search-results-title">No results matching "<span class='search-query'></span>"</h1>
            
        </div>
    </div>
</div>

                        </div>
                    </div>
                
            </div>

            
                
                <a href="when.html" class="navigation navigation-prev " aria-label="Previous page: 4.3. when">
                    <i class="fa fa-angle-left"></i>
                </a>
                
                
                <a href="observer-component.html" class="navigation navigation-next " aria-label="Next page: 4.5. (@)observer">
                    <i class="fa fa-angle-right"></i>
                </a>
                
            
        
    </div>

    <script>
        var gitbook = gitbook || [];
        gitbook.push(function() {
            gitbook.page.hasChanged({"page":{"title":"4.4. reaction","level":"1.4.4","depth":2,"next":{"title":"4.5. (@)observer","level":"1.4.5","depth":2,"path":"refguide/observer-component.md","ref":"refguide/observer-component.md","articles":[]},"previous":{"title":"4.3. when","level":"1.4.3","depth":2,"path":"refguide/when.md","ref":"refguide/when.md","articles":[]},"dir":"ltr"},"config":{"plugins":["github","edit-link","anchors","copy-code-button","github-buttons"],"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"pluginsConfig":{"github":{"url":"https://github.com/SangKa/mobx-docs-cn"},"search":{},"lunr":{"maxIndexSize":1000000,"ignoreSpecialCharacters":false},"fontsettings":{"theme":"white","family":"sans","size":2},"highlight":{},"github-buttons":{"buttons":[{"user":"SangKa","repo":"MobX-Docs-CN","type":"star","size":"small","count":true},{"user":"SangKa","repo":"MobX-Docs-CN","type":"fork","size":"small","count":true}]},"copy-code-button":{},"sharing":{"facebook":true,"twitter":true,"google":false,"weibo":false,"instapaper":false,"vk":false,"all":["facebook","google","twitter","weibo","instapaper"]},"edit-link":{"label":"完善文档","base":"https://github.com/SangKa/mobx-docs-cn/tree/master/docs"},"theme-default":{"styles":{"website":"styles/website.css","pdf":"styles/pdf.css","epub":"styles/epub.css","mobi":"styles/mobi.css","ebook":"styles/ebook.css","print":"styles/print.css"},"showLevel":false},"anchors":{}},"theme":"default","pdf":{"pageNumbers":true,"fontSize":12,"fontFamily":"Arial","paperSize":"a4","chapterMark":"pagebreak","pageBreaksBefore":"/","margin":{"right":62,"left":62,"top":56,"bottom":56}},"structure":{"langs":"LANGS.md","readme":"README.md","glossary":"GLOSSARY.md","summary":"SUMMARY.md"},"variables":{},"title":"MobX 中文文档","gitbook":"3.2.2"},"file":{"path":"refguide/reaction.md","mtime":"2018-09-18T13:06:39.966Z","type":"markdown"},"gitbook":{"version":"3.2.2","time":"2018-09-18T13:06:52.064Z"},"basePath":"..","book":{"language":""}});
        });
    </script>
</div>

        
    <script src="../gitbook/gitbook.js"></script>
    <script src="../gitbook/theme.js"></script>
    
        
        <script src="../gitbook/gitbook-plugin-github/plugin.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-edit-link/plugin.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-copy-code-button/toggle.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-github-buttons/plugin.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-search/search-engine.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-search/search.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-lunr/lunr.min.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-lunr/search-lunr.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-sharing/buttons.js"></script>
        
    
        
        <script src="../gitbook/gitbook-plugin-fontsettings/fontsettings.js"></script>
        
    

    </body>
</html>

